An investigation has revealed that King Charles and Prince William's estates, the Duchies of Lancaster and Cornwall, are generating millions of pounds by leasing land to public services and charities.

These estates are exempt from business taxes and use their revenues to support royal activities.

Collectively, they hold over 5,400 leases.

The Duchy of Lancaster, by retaining feudal rights over certain areas, is earning at least £28 million from windfarms and signed a £11.4 million lease with Guy's and St Thomas' NHS trust for ambulance storage.

The Duchy of Cornwall secured a £37 million lease of Dartmoor prison to the Ministry of Justice and charges the Royal Navy over £1 million for facilities use.

Despite environmental advocacy by the royals, many properties leased by the estates fail to meet energy efficiency standards, with over 13% scoring the lowest ratings.

Calls for reform include integrating the duchies into the crown estate and subjecting them to corporation tax.

Both duchies claim compliance with statutory requirements and emphasize ongoing environmental improvements.